The disclosures herein related generally to lathes and more particularly to an attachment used to acquire the dynamic relationship between the rotational axis of the lathe and the cutting tools used therewith.
In manufacturing there are processes that are used to cut and shape metal into desired geometries. One of these processes is known as turning. The equipment used in turning is called a lathe. The name turning, comes from the fact that the material to be cut, turns (rotates) about an axis. The cutting tool is external to the rotating material. The cutting tool approaches the material in a radial direction toward the rotational axis. As the tool comes in contact with the material, it removes material at a certain radial distance from the rotational axis.
The problem that exists, is acquiring the location of the rotational axis in relation to the cutting tool in the radial direction, to some level of precision. This requires precisely determining the relationship between a cutting tool and the rotational axis of a turning machine.
There are many approaches to acquiring the relationship between the rotational axis of the lathe and the cutting tool. Some, but not all, take into account the dynamic aspect of the relationship.
The traditional and oldest method of acquiring the relationship between the rotational dynamic axis of a lathe and the cutting tool, in the radial direction, is an iterative method known as the Cut/Measure/Cut method. In this method the operator will cut a part, measure the part and continue to cut and measure until the desired result is achieved. A variation of this method is to cut, measure and mathematically calculate the relationship, and make the final cut which achieves the desired result. These methods can result in material waste. The precision of both of these methods is highly dependent on the skill level of the machine operator.
The latest and most sophisticated method to define the relationship between the tool and the rotational axis is to use an electronic integrated probe. This is a device that is electronically and mechanically integrated into the operation of the machine. The probe is external to the rotational dynamic system. The probe is typically fixed to a surface near the rotational axis.
The traditional cut and measure approach is typically used to define the relationship between the probe and the rotational axis. From this point on, the relationship between the tool and the rotational axis is defined through the use of the probe.
The precision of the electronic integrated probe method is also highly dependent on the skill level of the operator initially defining the relationship between the probe and the rotational axis. In addition, if the relationship between the probe and the rotational axis changes, the probe will not detect this or compensate for it.
There is also static electronic probes that can be positioned on the rotational axis of a lathe, but they are designed to be used statically not rotating. These probes have names such as xe2x80x9celectric locating gages, electronic edge finder, electronic tool setter, electronic centering gage, electronic sensor and electronic offset gagexe2x80x9d.
There are also dynamic probes that can find the rotational axis of the lathe. However, these probes do not incorporate an electronic circuit for acquiring the rotational axis. These dynamic probes have names such as xe2x80x9cedge finders, center finders and wigglerxe2x80x9d.
U.S. Pat. No. 4,269,000 discloses an alignment fixture for use with an adjustable spindle nose device that rotatably supports a working member such as a honing mandrel to axially align the mandrel so that it rotates about a fixed axis along its length. The fixture comprises a housing having attached structure for mounting on a machine adjacent to a rotatable member to be aligned, an adjustable contact assembly including a first contact member mounted on the housing in position to engage the member to be aligned at one location therealong, a second contact assembly including a second contact member spaced from the first contact member for engaging the member to be aligned, apparatus for movably supporting the second contact assembly on the housing in position so that the second contact member is biased into engagement with the member to be aligned at a location axially spaced from the adjustable contact, an indicator assembly on the housing including a graduated scale and an indicator member movable relative to the scale, an operative connection between the second contact assembly and the movable indicator member whereby the indicator member indicates on the scale the position of the second contact member relative to the first contact member when both contacts are engaged with the member to be aligned, and apparatus for adjusting the position of the housing and the first and second contact assemblies thereon relative to the member after it is aligned to laterally locate the rotatable member.
In U.S. Pat. No. 4,879,817, a tool-setting probe has a stylus tip for contacting the tool tip, for setting the cutting tip of a cutting tool of a lathe. The stylus tip is generally cube-shaped. In addition to a conventional vertical datum surface for setting the tool in the horizontal direction, it has a 45E sloping datum surface. The tool is touched against both surfaces. The horizontal difference between the two contact positions is a measure of the height of the tool tip, enabling it to be set in the vertical direction.
Therefore, what is needed is a device for acquiring the location of the rotational axis in relation to the cutting tool in the radial direction.
One embodiment, accordingly, provides a rotational axis acquisition tool taking into consideration the dynamics of the centerline of a cylinder, a simple series circuit and a knowledge of the process. To this end, a rotational axis acquisition tool includes a rotatable mounting body having a first side and a second side opposite the first side. A sleeve has a first end fixedly mounted in the body and a second end extending from the first side. A dynamic cylinder is mounted on the sleeve and includes a radial face slidably abutting the second end of the sleeve. A resilient member is retained in the sleeve and is engaged for exerting a tensile force on the dynamic cylinder sufficient to maintain relative positioning of the radial face on the sleeve.
A principal advantage of this embodiment is the substantial limitation of material waste. With the Cut Measure Cut method there is always the chance that the operator will cut too much material resulting in a wasted piece. The other common approach is to have a set up piece which is discarded, resulting in waste. In addition, as the precision of the dimension desired increases, more cuts are typically required to achieve this higher precision. This increases the amount of time required to produce the part or parts, which is time waste.